Wavy background #2020
 Green  CC 0

CC0 and a seamless pattern from a tile drawn in Paint.net .

Source SliverKnight

 More Textures
Green Dust & Scratches #107
 Wall  CC BY-SA 3.0

Snap! It’s a pattern, and it’s not grayscale! Of course you can always change the color in Photoshop.

Source Atle Mo

Seamless Paper Texture (Pale Yellow) #1217
 Yellow  CC BY-SA 3.0

A seamless paper background texture colored in pale yellow. This seamless texture is ideal for those who need a yellow background image for their website. The texture resembles paper.

Source V. Hartikainen

Confectionary #1342
 Light  CC BY-SA 3.0

This could be a hippy vintage wallpaper.

Source Tileable Patterns

Floral design 94 #1792
 Yellow  CC 0

From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.

Source Firkin

Floral design 71 #2429
 Dark  CC 0

From a drawing in 'From Snowdon to the Sea. Striking stories of North and South Wales', Marie Trevelyan, 1895.

Source Firkin

Seamless tile 5 #1804
 Red  CC 0

Formed in Paint.net and vectorised in Vector Magic

Source Firkin

Stone Wall & Dark #1582
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Background pattern 235 (colour 2) #2254
 Blue  CC 0

To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Background pattern 252 #2162
 Dark  CC 0

Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Perforated White [email protected] #636
 Light  CC BY-SA 3.0

A bit of scratched up grayness. Always good.

Source Dmitry

Project [email protected] #120
 Paper  CC BY-SA 3.0

Light square grid pattern, great for a “DIY projects” sort of website, maybe?

Source Rafael Almeida

Gold Wall & Dark #1254
 Wall  CC 0

Zerro CC tillable texture of stones photographed and made by me. CC0

Source Sojan Janso

Prismatic Dots Background [email protected] #514
 Dark  CC 0

Prismatic Dots Background 7

Source GDJ

White Bed Sheet #821
 Light  CC BY-SA 3.0

Nothing like a clean set of bed sheets, huh?

Source Badhon Ebrahim

Green Fibers #91
 Dark  CC BY-SA 3.0

The green fibers pattern will work very well in grayscale as well.

Source Matteo Di Capua

Perforated White Leather #635
 Light  CC BY-SA 3.0

A bit of scratched up grayness. Always good.

Source Dmitry

Background pattern 334 #1729
 Dark  CC 0

Derived from an image that was uploaded to Pixabay by Kaz

Source Firkin

Double [email protected] #52
 Stripes  CC BY-SA 3.0

Horizontal and vertical lines on a light gray background.

Source Adam Anlauf

Connected #348
 Light  CC BY-SA 3.0

White circles connecting on a light gray background.

Source Mark Collins

Stone Wall & Gray #1500
 Stone  CC 0

Incoming catena. Stone & well. CC0 texture.

Source Unknow

Seamless Texture of Wood Planks #880
 Wood  CC BY-SA 3.0

Here's an yet another background for websites, with a seamless texture of wood planks this time.

Source V. Hartikainen

Prismatic Curved Diamond Pattern 4 No Background #541
 Diamond  CC 0

Prismatic Curved Diamond Pattern 4 No Background

Source GDJ

Square ornament 31 #2434
 Dark  CC 0

Drawn in Paint.net using the kaleidoscope plug-in and vectorised.

Source Firkin

Background pattern green #1944
 Green  CC 0

To get the tile this is based on, select the rectangle in Inkscape and use shift+alt+i.

Source Firkin

Background pattern black #2026
 Dark  CC 0

Remixed from a design seen in 'Burghley. The Life of William Cecil', William Charlton, 1857. The tile this is based on can be had by selecting the rectangle in Inkscape and using shift+alt+i.

Source Firkin

Decorative divider 212 #2343
 Dark  CC 0

Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.

Source Firkin

Vintage tile background (colour 3) #2246
 Green  CC 0

A background formed from an image of an old tile on the New York Metropolitan Museum of Art website. To get the base tile, select the rectangle in Inkscape and use shift-alt-i.

Source Firkin

Sponge A2-2 #2125
 Yellow  CC 0

CC0 textures, backgrounds.

Source SliverKnight